HR: 09:45h
AN: P31D-08    [Abstracts]
TI: MARCI Observations of Mesospheric Cloud Trails and Their Association with Extreme Vertical Ascent within Localized (10's of km), Short Duration (1-2 days) Dust Lifting Events
AU: * Clancy, R T
EM: clancy@spacescience.org
AF: Space Science Institute, 4750 Walnut Street Suite 205, Boulder, CO 80301, United States
AU: Wolff, M J
AF: Space Science Institute, 4750 Walnut Street Suite 205, Boulder, CO 80301, United States
AU: Cantor, B A
AF: Malin Space Science Systems, P.O. Box 910148, San Diego, CA 92191-0148, United States
AU: James, P B
AF: Space Science Institute, 4750 Walnut Street Suite 205, Boulder, CO 80301, United States
AU: Haberle, R M
AF: NASA Ames Research Center, Space Science Division Mail Stop 245-3, Moffett Field, CA 94035-1000, United States
AU: Malin, M C
AF: Malin Space Science Systems, P.O. Box 910148, San Diego, CA 92191-0148, United States
AB: The Mars Color Imager (MARCI) on board the Mars Reconnaissance Orbiter (MRO) employs wide-angle imaging (180 deg) in five visible color bands (420-750 nm) and two ultraviolet (uv) bands (260-320 nm). Due to the very dark uv, violet albedo of Mars surface and suspended dust, clouds appear with high contrast in MARCI uv, violet daily global image maps. During MARCI imaging prior to the July 2007 planet encircling dust veil (Ls=230-255 versus 265-), a set of striking cloud streaks or trails was located at mesospheric altitudes (50-80 km) based on distinct ground shadows cast from their sharp eastern termini (origins). These bright cloud trails are very linear, with >600 km longitudinal lengths accompanied by <60 km latitudinal widths and small but distinct NE-SW trends. Additional key aspects of these cloud trails are their association with specific regions on Mars (most notably at 20S, 35-43W) and their short timescales of formation and decay (hours). These spatial, temporal aspects of the observed mesospheric cloud trails suggest abrupt, localized surface forcing in which dust particles are lifted into the mesosphere and nucleate water ice particles which are rapidly transported westward as cloud trails in the strong easterly zonal winds of the Mars upper atmospheric circulation in this season. We present MARCI image observations of the cloud trails and their surface forcing dust lifting events, in the context of implied vertical dust propagation and mesospheric zonal wind velocities.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0343 Planetary atmospheres (5210, 5405, 5704)
DE: 3311 Clouds and aerosols
DE: 5210 Planetary atmospheres, clouds, and hazes (0343)
DE: 5405 Atmospheres (0343, 1060)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting